This invention relates to a sheet feeder for individually feeding sheets to a sheet treating machine, for example, a printing press, wherein a first sheet pile is carried by a main pile table and the respective uppermost sheet of the first sheet pile is feedable from a first sheet separting device, if desired via a first feed table, to the sheet treating machine, and with an auxiliary pile table carrying a second pile of sheets, of which the respective uppermost sheets are feedable by a second sheet separation device, if desired via a second feed table, to the sheet treating machine in place of the sheets from the main pile table.
In the case of such sheet feeders it is known to feed sheets to the sheet treating machine either from the first or from the second sheet pile.
On a change of the sheet feed from the one sheet pile to the other sheet pile, there comes a substantial interruption of operation, which is necessary for the changeover procedure.